What is Free energy: Definition and 302 Discussions
The thermodynamic free energy is a concept useful in the thermodynamics of chemical or thermal processes in engineering and science. The change in the free energy is the maximum amount of work that a thermodynamic system can perform in a process at constant temperature, and its sign indicates whether a process is thermodynamically favorable or forbidden. Since free energy usually contains potential energy, it is not absolute but depends on the choice of a zero point. Therefore, only relative free energy values, or changes in free energy, are physically meaningful.
The free energy is a thermodynamic state function, like the internal energy, enthalpy, and entropy.
Homework Statement
A. Explain the need for Gibbs Free Energy equation.
B. Explain what it means when:
\Delta G <0 \Delta G >0 \Delta G =0
Homework Equations
\Delta G= \Delta H-T \Delta S
The Attempt at a Solution
A. Gibbs eqn comes from the need to calculate the entropy of...
Hey guys, I'm hung up on the Gibbs Free Energy equations. I know that ?G° is the free energy change under standard conditions (1 M, 1 atm, 25ºC), and that it is characteristic for a given reaction. I think that when a reaction is occurring under conditions that are not standard the equation...
The total (free) energy for single molecule. The better if there is a free energy-volume(pressure) function.
I searched the APS and JCP,JPC journals,still cann't find it.
Thanks for your time.
Homework Statement
Calculate the Gibbs free energy for a van der Waals gas (up to an integration constant), assuming a fixed amount of material and temperature.
Homework Equations
P = \frac{NkT}{V-Nb} - \frac{aN^2}{V^2}
dG = -SdT + VdP + udN (where u is the chemical potential)
The...
Thermodynamics question: How much work can be obtained from sunlight?
It seems like a solar panel within the sun would not continuously generate electricity (else it could purely convert heat to work) but instead would emit as much black-body radiation as it absorbs. Back here the light is...
Homework Statement
Consider fuel cell using methane as fuel. Reaction is
CH^4 + 2O_2 -> 2H2O+CO_2
Assume room temperature and atmospheric temperature
Determine values of delta H (Helmholtz) and delta G (Gibbs) for this reaction for one mole of methane.
Question instructed the use of...
Hello,
We are two students trying to build a small scale Tesla Tower (http://en.wikipedia.org/wiki/Wardenclyffe_Tower) that perhaps would transmit electrical energy wirelessly through a house. But first, before we start building this, we are starting on a small scale electrical energy...
Homework Statement
Calculate the equilibrium constant for the reaction forming nitric oxide at room temperature, 25C. G= 1.73x10^5 J/mol, H = 180.5KJ/mol an S = 24.8J/(mol.K)
Homework Equations
ln K = -G/RT
The Attempt at a Solution
I subsiuted ln K = (-1.73x10^5) /...
I have a tube 1 m long and 1 m wide with an ideal fluid inside with a pressure of 1 bar.
I conect that tube of 1*1m with another tube of 1m long and 0.5m wide and this connected to another tube of 1 m and 0.25 m wide and so on
So i have a tube in which every 1 m of length the wideness of...
I'm not sure whether this belongs in the chemistry section, but since it concerns free energy, I decided to post it here.
My chemistry text, Zumdhal, says (without proof, I am self-studying a first year college-level chem course) that \Delta G = \Delta G^{\circ} + RTln(Q), where Q is the...
Hi
I am new in thermodynamics , and I thought you can help me
If it is valid dG=dW
May I say
dG=-Pdv
P=-dG/dv?
thanks in advance,Mariana
P=external pressure
G=Gibbs energy
W=maximum work
The relationship between free energy and the equilibrium constant is
Go = -RT ln K
By measuring the pH at various temperatures, the Kb for NH3(aq) was found to be temperature dependent, yielding the following values:
temperature (K) Kb
283 1.34 X 10-5
293 1.42 X 10-5
303 1.50 X...
\tau = k_{B} T
a) Find the expression for the free energy as a function of the temperature of the system with two states - one iwth eneryg zero and one with energy \epsilon_{0}
b) From the free energy find the expressions for the energy and entropy of the system
c) Plot the average energy...
A friend of mine asked me where the energy comes from in this setup:
Imagine a fan/windmill inside a box. The fan is only allowed 2 turn clockwise and is connected to an axel which exits the box.
The atmosphere will keep the air inside the box at, well, atmospheric temperateure. Every so...
could this be future free energy?
http://www.boinc.ch/~sleepsleep/blend/fe.png"
when the bowling ball drops down from left (air) tube, we would use its energy (due to gravity) to pull another bowling ball in (water) tube.
if u see the graphic, there is a "air" pad that to make the...
Forgive me if this sounds ignorant; I have no professional knowledge of physics. But I've wondered if it is possible to obtain free energy from gravity in this manner: I remember seeing a documentary on an attempt to build the world's tallest building. Apparently, it could only be built so tall...
I don't know where to start with this problem. I must be missing an equation or something...
Q: Pb(s)+2H^{+}(aq)\rightarrow Pb^{2+}(aq)+H_2(g) \,\,\,\,\,\,\,\,E^{\degree}_{cell}=+0.126V
What is the \Delta G^{\degree} in \frac{kJ}{mol} for this reaction.
a) -24
b) 24
c) -12
d) 12
e) 50...
Hi to everyone at the forum.
I've attached the question in word format so you can see it properly but
it is basically this:
-----
The Gibb's Free Energy is:
G(T, P, N) = U - TS + PV
Where N is the number of particles. (Only one type of particle is present).
Explain why the...
Calculate the gibbs free energy for a reaction which has a standard enthalpy = -196kJ/mol and standard entropy = 151 J/K mol at 32C.
G = -196 KJ/MOL -[-305.15 K*0.15] = -242KJ
Thank you.
Are my final values correct?
1. Determine the free energy change associated with the formation of methanol from carbon monoxide and hydrogen gas if the partial pressure of CO is 1.0700 atm, H2 is 2.2800 atm, and CH3OH is 0.0600 atm at 298K. The standard free energy of formation for methanol...
my objective was that gravity caused movement in an object without lowering the center of mass
i built a balance that has the center of gravity in the axe:
i used a 60 cm long 1 cm thick wood beam, i put a nail in the middle as an axe,
i put 100 grams of plastiline in each end of the...
Does anyone have any good web sites on free energy? I heard about this guy who was able to make a current go through an open circuit just by looking at it or something... sounds pretty interesting.
this idea came after an experiment trying to improve the rotation speed of my yoyo:
i thought that increasing the radius of the axle of the yoyo,its thickness,i would increase the rotation speed but it turn out to decrease the rotational speed caused by gravity in the yoyo
the yoyo...
I found this just a while ago...
http://amasci.com/freenrg/magputt.txt
The whole idea is to take a magnetron froma microwave oven and install it in a combustion engine. The problem is this guy says it is to be used as a steam turbine, not a combustion engine (and that it is the most...
Have you ever heard of SMOT?
There is a website saying about free energy.
http://jnaudin.free.fr/html/smotidx.htm
What's your opinion?
Why the author haven't succeeded to create a cycle?
Guys,
I hope you know the principal of WATER-FOUNTAIN (like the one you see in park etc... that don't need much additional mantinance or EXTERNAL energy to operate)
See the pic (attached.)
If the water in top bucket is made to fall directly on the top of the blades of (small)dynamo...
would anyone happen to know what the expression for an isothermal change in Gibbs free energy for a liquid is when the pressure changes from pi to pf. Also an expression for when its a perfect gas?
i can't seem to figure them out.. and how would they be deduced?
i've come across one equation...
Okay, first I explain what I think I understand, then what my problem is.
As I understand it, if you have two massive bodies connected by a perfect frictionless spring, so that they fall towards each other by gravity and then bounce back from the spring, they will eventually come to rest with...
hey i seem to be having a lot of trouble with this type of question:
Calculate the change in Gibbs energy of 35g of ethanol (mass density = 0.789g cm-3) when the pressure is increased isothermally from 1 atm to 3000 atm.
in my notes i have that dG=V(Pf-Pi) and search up on the net that...
Can anyone point me to some source code for monte carlo methods for free energy estimation. Standard metropolis/hamiltonian don't work since its the integral not the expectation I'm interested in.
candidates seem to be path sampling/ bridge sampling and annealed importance sampling of which...
Let’s say we have a 1 mol system in a state A (Pa,Va,Ta are given) and we take it to a state B(Pb,Vb are given) . We want to know what’s the maximum work we can give to a reversible work source. Considering the process is carried out attached to a 150 K heat source, the only data available is...
"Free" energy at home
http://www.perendev-power.com/home.htm
http://www.freeenergynews.com/Directory/Perendev/MagneticMotor/KeithAnderson_statement/
http://curezone.com/forums/m.asp?f=237&i=822
I haven't seen any discussion here about these magical devices... Your comments?
free energy: please "chew and digest" idea
Hi, I am new to this board.. but I've read enough about the nut-theories pertaining to "Vacuum energy", macro-quantum teleportation, and many out there ideas..
I do have an idea, that does pertain to "free energy", but before I am debunked.. let's...
Hi,
I'm working on a problem of the thermal stability of a protein. Conventionlly, people compare protein thermal stability in terms of the Gibbs free energy difference between the native and unfolded state. So if it reversibly falls apart, then for N <==> U, DG(N-U) is accessed from the...
Hey guys;
I've a question. How do enzymes lower the free energy of activation?
My thinking is that the enzyme binds, and when it binds it alters the shape of whatever it binds to, and the altered shape is energetically favored to the unaltered shape for the reaction. This is purely...
interesting article and lots of links to anti-grav and free energy. :smile:
http://www.para-normal.com/nuke/html/modules.php?name=News&file=article&sid=1560&mode=thread&order=0&thold=0
perpetual motion and free energy possible?
acording to many inventors, they have invented a perpetual motion machine, from a guy in Norway, USA, Canada, France. but according to todays laws in physics, perpetual motion is imposible, one guy said aliens from Kandlon, or something, visited him...
It’s so simple to produce unlimited, clean electricity that my design must be flawed. Let me know where my thinking has gone astray.
This is a gravitational generator that uses the Earth’s gravity to produce electricity. We start with a standard turbine generator such as those used in...
Hi everybody,
I'm working on a project aiming to determine what are the differents ways to measure the free energy (gibbs) and the enthalpy of reactions.
And I have no idea.
If you know some equipments or some procedure to measure it or also where i should look for it, I would be very happy...
Hi everybody,
I'm working on a project aiming to determine what are the differents ways to measure the free energy (gibbs) and the enthalpy of reactions.
And I have no idea.
If you know some equipments or some procedure to measure it or also where i should look for it, I would be very happy...
Hi everybody,
I'm working on a project aiming to determine what are the differents ways to measure the free energy (gibbs) and the enthalpy of solutions or any bodies.
And I have no idea.
If you know some equipment or some procedure to measure it, I would be very happy.
Thanks.
I have an experiment here that proves that free
energy exists.
First you take 2 identical capacitors each consists of 2 plates 1M square,one has a
dielectric 1M square sandwiched between the 2
plates the other capacitor has an air gap between
the 2 plates.Lets say the dielectric constant...
Your'll all missing the point. There is no such thing as free energy. There is no such thing as anti gravity. There is no such thing as Gravity. We all ready have a G.U.T. Einstein's other theory of gravity unites the four four forcse of nature. They don't tell you about it. They don't teach it...